#include <iostream>

constexpr int func(int a)
{
    return a * 10;
}

template<int size>
class Test
{
private:
    char str[size];
};

class A
{
private:
    int a;
};

constexpr int sum(int x)
{
    int count = 0;
    while (x != 0)
    {
        x--;
        count++;
    }
    return count;
}
int main()
{
    //编译时运算，不再是一个普通的变量，可以作为一个常量
    constexpr int a = 10;
    Test<a> t;
    constexpr int a = 10 * 10;
    std::cout << func(a) << std::endl;

    char str[sum(4)];
    return 0;
}